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+ − 1 ///////////////////////////////////////////////////////////////////////////////
+ − 2 /// -*- coding: UTF-8 -*-
+ − 3 ///
+ − 4 /// \file Discovery/Inc/crcmodel.h
+ − 5 /// \brief Rocksoft CRC Model Algorithm
+ − 6 /// \author Ross Williams (ross@guest.adelaide.edu.au.) and Heinrichs Weikamp
+ − 7 /// \date 3 June 1993
+ − 8 ///
+ − 9 /// \details
+ − 10 ///
+ − 11 /// This is the header (.h) file for the reference
+ − 12 /// implementation of the Rocksoft^tm Model CRC Algorithm. For more
+ − 13 /// information on the Rocksoft^tm Model CRC Algorithm, see the document
+ − 14 /// titled "A Painless Guide to CRC Error Detection Algorithms" by Ross
+ − 15 /// Williams (ross@guest.adelaide.edu.au.). This document is likely to be in
+ − 16 /// "ftp.adelaide.edu.au/pub/rocksoft".
+ − 17 ///
+ − 18 /// Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia.
+ − 19 ///
+ − 20 /// $Id$
+ − 21 ///////////////////////////////////////////////////////////////////////////////
+ − 22 /// \par Copyright (c) 2014-2018 Heinrichs Weikamp gmbh
+ − 23 ///
+ − 24 /// This program is free software: you can redistribute it and/or modify
+ − 25 /// it under the terms of the GNU General Public License as published by
+ − 26 /// the Free Software Foundation, either version 3 of the License, or
+ − 27 /// (at your option) any later version.
+ − 28 ///
+ − 29 /// This program is distributed in the hope that it will be useful,
+ − 30 /// but WITHOUT ANY WARRANTY; without even the implied warranty of
+ − 31 /// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ − 32 /// GNU General Public License for more details.
+ − 33 ///
+ − 34 /// You should have received a copy of the GNU General Public License
+ − 35 /// along with this program. If not, see <http://www.gnu.org/licenses/>.
+ − 36 //////////////////////////////////////////////////////////////////////////////
+ − 37
+ − 38 /******************************************************************************/
+ − 39 /* Start of crcmodel.h */
+ − 40 /******************************************************************************/
+ − 41 /* */
+ − 42 /* Author : Ross Williams (ross@guest.adelaide.edu.au.). */
+ − 43 /* Date : 3 June 1993. */
+ − 44 /* Status : Public domain. */
+ − 45 /* */
+ − 46 /* Description : This is the header (.h) file for the reference */
+ − 47 /* implementation of the Rocksoft^tm Model CRC Algorithm. For more */
+ − 48 /* information on the Rocksoft^tm Model CRC Algorithm, see the document */
+ − 49 /* titled "A Painless Guide to CRC Error Detection Algorithms" by Ross */
+ − 50 /* Williams (ross@guest.adelaide.edu.au.). This document is likely to be in */
+ − 51 /* "ftp.adelaide.edu.au/pub/rocksoft". */
+ − 52 /* */
+ − 53 /* Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia. */
+ − 54 /* */
+ − 55 /******************************************************************************/
+ − 56 /* */
+ − 57 /* How to Use This Package */
+ − 58 /* ----------------------- */
+ − 59 /* Step 1: Declare a variable of type cm_t. Declare another variable */
+ − 60 /* (p_cm say) of type p_cm_t and initialize it to point to the first */
+ − 61 /* variable (e.g. p_cm_t p_cm = &cm_t). */
+ − 62 /* */
+ − 63 /* Step 2: Assign values to the parameter fields of the structure. */
+ − 64 /* If you don't know what to assign, see the document cited earlier. */
+ − 65 /* For example: */
+ − 66 /* p_cm->cm_width = 16; */
+ − 67 /* p_cm->cm_poly = 0x8005L; */
+ − 68 /* p_cm->cm_init = 0L; */
+ − 69 /* p_cm->cm_refin = TRUE; */
+ − 70 /* p_cm->cm_refot = TRUE; */
+ − 71 /* p_cm->cm_xorot = 0L; */
+ − 72 /* Note: Poly is specified without its top bit (18005 becomes 8005). */
+ − 73 /* Note: Width is one bit less than the raw poly width. */
+ − 74 /* */
+ − 75 /* Step 3: Initialize the instance with a call cm_ini(p_cm); */
+ − 76 /* */
+ − 77 /* Step 4: Process zero or more message bytes by placing zero or more */
+ − 78 /* successive calls to cm_nxt. Example: cm_nxt(p_cm,ch); */
+ − 79 /* */
+ − 80 /* Step 5: Extract the CRC value at any time by calling crc = cm_crc(p_cm); */
+ − 81 /* If the CRC is a 16-bit value, it will be in the bottom 16 bits. */
+ − 82 /* */
+ − 83 /******************************************************************************/
+ − 84 /* */
+ − 85 /* Design Notes */
+ − 86 /* ------------ */
+ − 87 /* PORTABILITY: This package has been coded very conservatively so that */
+ − 88 /* it will run on as many machines as possible. For example, all external */
+ − 89 /* identifiers have been restricted to 6 characters and all internal ones to */
+ − 90 /* 8 characters. The prefix cm (for Crc Model) is used as an attempt to avoid */
+ − 91 /* namespace collisions. This package is endian independent. */
+ − 92 /* */
+ − 93 /* EFFICIENCY: This package (and its interface) is not designed for */
+ − 94 /* speed. The purpose of this package is to act as a well-defined reference */
+ − 95 /* model for the specification of CRC algorithms. If you want speed, cook up */
+ − 96 /* a specific table-driven implementation as described in the document cited */
+ − 97 /* above. This package is designed for validation only; if you have found or */
+ − 98 /* implemented a CRC algorithm and wish to describe it as a set of parameters */
+ − 99 /* to the Rocksoft^tm Model CRC Algorithm, your CRC algorithm implementation */
+ − 100 /* should behave identically to this package under those parameters. */
+ − 101 /* */
+ − 102 /******************************************************************************/
+ − 103
+ − 104 #ifndef CRC_MODEL_H
+ − 105 #define CRC_MODEL_H
+ − 106
+ − 107 /******************************************************************************/
+ − 108
+ − 109 /* The following definitions are extracted from my style header file which */
+ − 110 /* would be cumbersome to distribute with this package. The DONE_STYLE is the */
+ − 111 /* idempotence symbol used in my style header file. */
+ − 112
+ − 113 #ifndef DONE_STYLE
+ − 114
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+ − 115 #include <stdbool.h>
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+ − 116
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+ − 117 typedef unsigned long ulong;
+ − 118 typedef unsigned char * p_ubyte_;
+ − 119
+ − 120 #ifndef TRUE
+ − 121 #define FALSE 0
+ − 122 #define TRUE 1
+ − 123 #endif
+ − 124
+ − 125 /* Change to the second definition if you don't have prototypes. */
+ − 126 #define P_(A) A
+ − 127 /* #define P_(A) () */
+ − 128
+ − 129 /* Uncomment this definition if you don't have void. */
+ − 130 /* typedef int void; */
+ − 131
+ − 132 #endif
+ − 133
+ − 134 /******************************************************************************/
+ − 135
+ − 136 /* CRC Model Abstract Type */
+ − 137 /* ----------------------- */
+ − 138 /* The following type stores the context of an executing instance of the */
+ − 139 /* model algorithm. Most of the fields are model parameters which must be */
+ − 140 /* set before the first initializing call to cm_ini. */
+ − 141 typedef struct
+ − 142 {
+ − 143 int cm_width; /* Parameter: Width in bits [8,32]. */
+ − 144 ulong cm_poly; /* Parameter: The algorithm's polynomial. */
+ − 145 ulong cm_init; /* Parameter: Initial register value. */
+ − 146 bool cm_refin; /* Parameter: Reflect input bytes? */
+ − 147 bool cm_refot; /* Parameter: Reflect output CRC? */
+ − 148 ulong cm_xorot; /* Parameter: XOR this to output CRC. */
+ − 149
+ − 150 ulong cm_reg; /* Context: Context during execution. */
+ − 151 } cm_t;
+ − 152 typedef cm_t *p_cm_t;
+ − 153
+ − 154 /******************************************************************************/
+ − 155
+ − 156 /* Functions That Implement The Model */
+ − 157 /* ---------------------------------- */
+ − 158 /* The following functions animate the cm_t abstraction. */
+ − 159
+ − 160 void cm_ini P_((p_cm_t p_cm));
+ − 161 /* Initializes the argument CRC model instance. */
+ − 162 /* All parameter fields must be set before calling this. */
+ − 163
+ − 164 void cm_nxt P_((p_cm_t p_cm,int ch));
+ − 165 /* Processes a single message byte [0,255]. */
+ − 166
+ − 167 void cm_blk P_((p_cm_t p_cm,p_ubyte_ blk_adr,ulong blk_len));
+ − 168 /* Processes a block of message bytes. */
+ − 169
+ − 170 ulong cm_crc P_((p_cm_t p_cm));
+ − 171 /* Returns the CRC value for the message bytes processed so far. */
+ − 172
+ − 173 /******************************************************************************/
+ − 174
+ − 175 /* Functions For Table Calculation */
+ − 176 /* ------------------------------- */
+ − 177 /* The following function can be used to calculate a CRC lookup table. */
+ − 178 /* It can also be used at run-time to create or check static tables. */
+ − 179
+ − 180 ulong cm_tab P_((p_cm_t p_cm,int index));
+ − 181 /* Returns the i'th entry for the lookup table for the specified algorithm. */
+ − 182 /* The function examines the fields cm_width, cm_poly, cm_refin, and the */
+ − 183 /* argument table index in the range [0,255] and returns the table entry in */
+ − 184 /* the bottom cm_width bytes of the return value. */
+ − 185
+ − 186 /******************************************************************************/
+ − 187
+ − 188 #endif // CRC_MODEL_H